检索结果-南通市图书馆

Is the PhyloCode better than Linnaean system?—— New development and debate on biologi-cal nomenclatural issues

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第3期48卷 308-312页

作者： GAO Keqin & SUN Yuanlin school of earth and space sciences, peking university, beijing 100871, china school of earth and space sciences Peking University Beijing 100871 China

The Linnaean system provides ultimate means governing biological nomenclature and classification. With series of modification, this system has admirably served bio-logical sciences for some 250 years. The new PhyloCode, however, advocates the phylogenetic nomenclature that radically alternates the current nomenclatural rules. The new proposals upset many systematic biologists and have provoked hot debate on nomenclatural issues. Binomial no-menclature and hierarchical classification are the key com-ponents of the Linnaean system. Proposed abandonment of these in the PhyloCode is widely criticized for it would not help to promote systematics but create chaos. It is not the Linnaean system but the phylogenetic nomenclature that should be abandoned.

关键词：生物分类生物命名法林奈系统系统代码法特点

维普期刊数据库

Raman OH stretching vibration of ice Ih

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2009年第11期19卷 1651-1654页

作者： Qiang Sun~*,Haifei Zheng The school of earth and space sciences,peking university,beijing 100871,china The school of earth and space sciences Peking University Beijing 100871 China

From our recent research on ice Ih(hexagonal ice),we deduce that free OH groups exist at the ice surface and that dangling OH influences the interior of the proton-disordered ***,exploiting recent research by others on water molecular clusters,we propose a new interpretation for the Raman OH stretching vibration of ice *** deconvolute the Raman OH stretching vibration of ice Ihinto four sub-bands,with each sub-band being ascribed to OH vibrations engaged in different types of hydrogen bonding.

关键词： Raman Hydrogen bonding Ice I_h

Skara hunanensis a new species of Skaracarida (Crustacea) from Upper Cambrian (Furongian) of Hunan,south china

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第8期17卷 934-942页

作者： Liu Jie Dong Xiping~(**) (school of earth and space Science,peking university,beijing 100871,china) school of earth and space Science Peking University Beijing 100871 China

The fossils of Orsten-type preservation are as famous as Chengjiang Fauna in the world,but it was not until 2005 that the Orsten-type fossils represented by Skaraearida and Phosphatocopida were first reported to be found in western Hunan,South china. Here,we report the systematic paleontology of all the exquisitely preserved specimens belonging to *** were found at a same horizon of Upper Cambrian (Furongian) in Wangcun section,western Hunan,south china,assigned to a new species Skara huna- nensis *** hunanensis is characterized by small,soft-integumented,marine forms with slender,annulate body;labrum large and ventrocaudally directed;uniramous antennulae;biramous antennae and mandibulae;maxillas and maxillipeds of the same shape;all postantennular limbs join a short cephalic filter *** body has two tagmata:a cephalon with five pairs of well developed ap- pendages and a trunk composed of 11 ring-shaped conical segments.

关键词： Skara hunanensis Skaracarida Crustacea Upper Cambrian Furongian Hunan

Biodegradation of heavy oils by halophilic bacterium

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2009年第8期19卷 997-1001页

作者： Ruixia Hao , Anhuai Lu school of earth and space sciences, peking university, beijing 100871, china school of earth and space sciences Peking University Beijing 100871 China

A halophilic bacterial strain TM-1 was isolated from the reservoir of the Shengli oil field in East china. Strain TM-1, which was found to be able to degrade crude oils, is a gram-positive non-motile bacterium with a coccus shape that can grow at temperatures of up to 58 °C and in 18% NaCl solution. Depending on the culture conditions, the organism may occur in tetrads. In addition, strain TM-1 produced acid from glucose without gas formation and was catalase-negative. Furthermore, strain TM-1 was found to be a facultative aerobe capable of growth under anaerobic conditions. Moreover, it produced butylated hydroxytoluene, 1,2-benzenedicarboxylic acid-bis ester and dibutyl phthalate and could use different organic substrates. Laboratory studies indicated that strain TM-1 affected different heavy oils by degrading various components and by changing the chemical properties of the oils. In addition, growth of the bacterium in heavy oils resulted in the loss of aromatic hydrocarbons, resins and asphaltenes, and enrichment with light hydrocarbons and an overall redistribution of these hydrocarbons.

关键词： Halophilic bacterium Metabolite Heavy oil Degradation

Implications of micro-compositions of garnet and biotite from high-grade meta-pelites

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第2期16卷 209-214页

作者： ZHOU Xiwen, WEI Chunjing, and ZHANG Shangkun ( Institute of Geology, CAGS, beijing 100037, china school of earth and space sciences, peking university, beijing 100871, china china university of Geo-sciences, beijing 100083, china) Institute of Geology GAGS Beijing 100037 China school of earth and space sciences Peking University Beijing 100871 China china university of Geo-sciences Beijing 100083 China

Based on detailed studies on the compositional zoning of garnet and biotite in pelitic rocks from the Jingshan group of granulite facies in north Jiaodong, P-T pseudosections with isopleths of Fe/(Fe + Mg) in garnet and biotite were calculated in the KF-MASH system for two representative rocks of sillimanite-garnet-cordierite-biotite gneiss ( Vbi/ Vg>1 ) and sillimanite-garnet gneiss (Vbi/ Vg 1 can nearly preserve their peak compositions, and biotites in garnet-rich rocks with Vbi/Vg<0. 2 cannot preserve their peak compositions due to the influence of grain-boundary fluid.

关键词： high-grade meta-pelites THERMOCALC P-T pseudosection peak compositions of garnet and biotite.

Microstructural and deformational studies on mylonite in the detachment faults of Yalashangbo dome, North Himalayan domes zone

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第11期15卷 1005-1013页

作者： ZHANG Bo, ZHANG Jinjiang, GUO Lei and WANG Weiliang (Department of Geology, school of earth and space sciences, peking university, beijing 100871, china) Department of Geology School of Earth and Space Sciences Peking University Beijing 100871 China

The Yalashangbo dome, located at the eastern end of North Himalayan domes zone, has a geometry and structure similar to those of a metamorphic core complex. Ductile shear zones formed the detachment system around the dome and these zones are composed of garnet-bearing phyllonite, mylonitic schist, mylonitic gneiss and mylonitic granite. Ductile shear fabrics developed well in my-lonitic rocks, and penetrative lineation and foliation were formed by stretched quartz and feldspar and preferred orientation of mica. Polar Mohr diagram method is used to calculate the kinematic vorticity numbers of the shear zones in the detachment system. Results indicate that the shear zone is a thinned shear zone (thinning of 23 % ) in an extensional setting which underwent a general shear dominated by simple shear. Comparison of the vorticity numbers between the northern and southern flanks of the Yalashangbo dome shows that the dome is an asymmetric system formed by a north-northwest-directed detaching unanimously. Statistical fractal analysis shows that the shapes of dynamically recrystallized quartz grains in the mylonites have characteristics of self-similarity, with fractal numbers ranging from 1.05 to 1.18. From these fractal numbers, the strain rate of the rock was deduced from 10-9.2S-1 to 10-7.3S-1, the differential paleao-stress was 13.7-25.6 MPa during the deformation happened at a temperature over 500 ℃. The ductile shear zones in the detachment system around Yalashangbo dome were formed under a high green-schist grade condition or happened simultaneously with the intrusion of granite.

关键词： Yalashangbo dome ductile shear zone kinematic vorticity fractal analysis deformation temperature strain rate.

Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2009年第22期54卷 4148-4160页

作者： NIU Yaoling1,2,3 1 Department of earth sciences, Durham university, Durham DH1 3LE, UK 2 school of earth sciences and Resources, china university of Geosciences, beijing 100083, china 3.school of earth and space sciences, peking university, beijing 100871, china Department of earth sciences Durham University Durham DH1 3LE UK school of earth sciences and Resources China University of Geosciences Beijing 100083 China school of earth and space sciences Peking University Beijing 100871 China

Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with "hotspots" or "mantle plumes". While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, our current understanding on the origin of OIB source material remains unsatisfactory, and some prevailing ideas need revision. One of the most popular views states that OIB source material is recycled oceanic crust (ROC). Among many problems with the ROC model, the ocean crust is simply too depleted (e.g., [La/Sm]PM > 1) OIB. Another popular view states that the enriched component of OIB comes from recycled continental crust (RCC, i.e.; terrigenous sediments). While both CC and OIB are enriched in many incompatible elements (e.g., both have [La/Sm]PM >>1), the CC has characteristic enrichment in Pb and deletion in Nb, Ta, P and Ti. Such signature is too strong to be eliminated such that CC is unsuitable as source material for OIB. Plate tectonics and mantle circulation permit the presence of ROC and RCC materials in mantle source regions of basalts, but they must be volumetrically insignificant in contributing to basalt magmatism. The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H2O and CO2 rich incipient melt may form in the seismic low velocity zone (LVZ). This melt will rise because of buoyancy and concentrate into a melt rich layer atop the LVZ to metasomatize the growing lithosphere, forming the metasomatic vein lithologies. Erupted OIB melts may have three components: (1) fertile OIB source material from depth that is dominant, (2) the melt layer, and (3) assimilation of the metasomatic

关键词：岩石成因论海洋 OIB 矿物学

维普期刊数据库

Petrogenesis and significance of the Hongshan syenitic pluton,South Taihang: zircon SHRIMP U-Pb age, chemical compositions and Sr-Nd isotopes

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第2期16卷 192-200页

作者： ZHOU Ling and CHEN Bin (Key Laboratory of Orogenic Belts and Crustal Evolution, MOE, school of earth and space sciences, peking university, beijing 100871, china) Key Laboratory of Orogenic Belts and Crustal Evolution MOE School of Earth and Space Sciences Peking University Beijing 100871 China

The Hongshan syenitic pluton (South Taihang) is mainly made up of hornblende syenite and minor granite. SHRIMP zircon dating yields a U-Pb age of 135±2.7 Ma for the emplacement of the pluton, while biotite Rb-Sr isotopic data give an isochron of 120. 3±2.4 Ma. Hongshan syenites show low silica, high alkalis and LILE such as Sr, and exhibit negligible Eu anomalies or slightly positive anomalies in the REE patterns. The syenites show quite enriched isotopic compositions with Isr from 0.7052 to 0. 7102 and εNd(t) from -7.5 to - 11.1. Petrogenesis of the pluton can be that partial melting of an enriched lithospheric mantle gave birth to an alkali basaltic magma, which subsequently underplated in the lower crust and experienced a coupled fractionation of ferromagnesian phases like pyroxene and hornblende and minor ( china Plateau" in the Mesozoic.

关键词： syenite zircon SHRIMP Nd-Sr isotopes Taihang North china craton.

On Riemann-Finsler geometry

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第6期43卷 447-450页

作者： MO Xiaohuan school of Mathematical sciences, peking university, beijing 100871, china school of Mathematical sciences Peking University Beijing China

The history of Finsler geometry is reviewed and briefly recent development in Finsler geometry and its application is completed systematically. Furthermore, an interesting open problem has been proposed in this field.

关键词： Finsler space Chern connection Hilbert form Minkowski potential projective sphere bundle.

维普期刊数据库